Spin effects on decay dynamics of charge-separated states generated by photoinduced electron transfer in zinc porphyrin-naphthalenediimide dyads

被引:46
作者
Mori, Y [1 ]
Sakaguchi, Y [1 ]
Hayashi, H [1 ]
机构
[1] RIKEN, Inst Phys & Chem Res, Mol Photochem Lab, Wako, Saitama 3510198, Japan
关键词
D O I
10.1021/jp013453e
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Photoexcitation of zinc porphyrin-bridge-naphthalenediimide (ZP-B-NI) dyads, I and 2, generated the short- and long-distance charge-separated (CS) states, [ZP(circle+)-B-Nl(circle-)], through the intramolecular electron-transfer from excited ZP to NI in solvents of various polarity. The energy level of [ZP(circle+)-B-NIcircle-] was either higher (in benzene and 1,4-dioxane) or lower (in solvents of higher polarity) than that of 3Zp*-B-NI.When generated in the singlet spin state, the short-distance CS state derived from I rapidly (10(9)-10(10) s(-1)) decayed through the charge recombination (CR) leading to the ground state. On the other hand, when generated from the triplet excited state of 1, the decay of the CS state was much slower and showed magnetic field effects attributable to the level-crossing mechanism. For the long-distance CS state derived from 2, the decay dynamics and its magnetic field dependence exhibited quite different features. To examine the effects of a neighboring additional radical on the decay dynamics of these CS states, three-spin CS states [ZP(circle+)-B-NIcircle--Rcircle] were generated from 1Rcircle and 2Rcircle, in which 2,2,6,6-tetramethyl-l-piperidinoxy radical (Rcircle) was connected to the NI part in 1 and 2, respectively. The decay rate of [ZP(circle+)-B-NIcircle--Rcircle] derived from 1Rcircle was much faster than that of [ZP(circle+)-B-NIcircle-] derived from 1. For the CS state generated from 2Rcircle, the initial decay could be retarded compared to the CS state from 2 through the equilibration between the doublet and quartet spin states. The observed effects of Re on the decay processes of the CS states are attributed to the alteration of the energy gap between the states with different spin multiplicities and to the efficient conversion between the doublet and quartet spin states induced by the dipole-dipole interaction between NIcircle- and Rcircle.
引用
收藏
页码:4453 / 4467
页数:15
相关论文
共 132 条
[1]   Enhancement of intersystem crossing by substitution: assignment of a long-lived triplet state by magnetic field effects in a non-viscous medium [J].
Aich, S ;
Basu, S .
CHEMICAL PHYSICS LETTERS, 1997, 281 (4-6) :247-253
[2]   Electron transfer through-space or through-bonds? A novel system that permits, a direct evaluation [J].
Arimura, T ;
Ide, S ;
Suga, Y ;
Nishioka, T ;
Murata, S ;
Tachiya, M ;
Nagamura, T ;
Inoue, H .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2001, 123 (43) :10744-10745
[3]   MAGNETIC-FIELD EFFECTS ON CHEMILUMINESCENT FLUID SOLUTIONS [J].
ATKINS, PW ;
EVANS, GT .
MOLECULAR PHYSICS, 1975, 29 (03) :921-935
[4]   DENSITY-FUNCTIONAL THERMOCHEMISTRY .3. THE ROLE OF EXACT EXCHANGE [J].
BECKE, AD .
JOURNAL OF CHEMICAL PHYSICS, 1993, 98 (07) :5648-5652
[5]  
Bencini A.Gatteschi., 1990, EPR of Exchange Coupled Systems
[6]   THE SINGLET-TRIPLET SPLITTING OF THE PRIMARY RADICAL PAIR IN THE BACTERIAL PHOTOSYNTHETIC REACTION-CENTER [J].
BIXON, M ;
JORTNER, J ;
MICHELBEYERLE, ME .
ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS, 1993, 180 :193-208
[7]   Charge transport in DNA via thermally induced hopping [J].
Bixon, M ;
Jortner, J .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2001, 123 (50) :12556-12567
[8]  
BIXON M, 1999, ELECT TRANSFER ISO 2
[9]  
BIXON M, 1999, ELECT TRANSFER ISO 1
[10]   CHEMICALLY MEDIATED FLUORESCENCE YIELD SWITCHING IN NITROXIDE FLUOROPHORE ADDUCTS - OPTICAL SENSORS OF RADICAL REDOX REACTIONS [J].
BLOUGH, NV ;
SIMPSON, DJ .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1988, 110 (06) :1915-1917